• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Engine Car is idling rough and cutting out

  • Thread starter Thread starter keel
  • Start date Start date Aug 23, 2023

keel

Active Member
Aug 23, 2020
227
80
38
Seattle, Wa
Aug 23, 2023
#1
  • Aug 23, 2023
  • #1
Just finished an engine rebuild and the car ran perfect for about 500 miles or so, but now it is intermittently running poorly (doesn't seem mechanically related). Initially, it was idling low and rough and would cut out under load and buck occasionally, and the CEL came on. Then the CEL would turn off and the car would run as if nothing happened. This continued for about 10 minutes until I got home. I dumped codes when I got home, and got 67, 81, 82, and 84. However, before it dumped those codes, the CEL flickered briefly. Not really sure what that means but might be important to include.

I understand that these are EGR codes, I have deleted the EGR system completely and have been running an EGR eliminator plug that I got on LMR a while ago that they no longer sell. It has worked great for the last 3 years.

What could be the issue?
 
Last edited: Aug 23, 2023

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,924
10,570
203
polk county florida
Aug 24, 2023
#2
  • Aug 24, 2023
  • #2
You have a wire connection issue. I would start with the ignition wiring looking for bad connections/cracked wires.
Start by wiggling crap.
 
Reactions: keel

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,924
10,570
203
polk county florida
Aug 24, 2023
#3
  • Aug 24, 2023
  • #3
You have a wire connection issue. I would start with the ignition wiring looking for bad connections/cracked wires.
Start by wiggling crap.
 

AeroCoupe

lube between the nut and the face. I know my lubes
Founding Member
Oct 28, 2001
5,882
4,007
183
Claremore, OK
Aug 24, 2023
#4
  • Aug 24, 2023
  • #4
So a Code 67 has nothing to do with the EGR but I doubt it’s the cause of you issues. See Post #2 in this thread:

Code 67

1988 Mustang factory V8, 5 speed car. Mass Air conversion done with A9L computer. When KOEO is done I get code 67 along with some EGR codes too. Trying to fix the 67 code. When codes were pulled a/c was off, car in neutral and clutch pushed in. A Tr 3550 tranny is in the car and the sensor...
stangnet.com
 

keel

Active Member
Aug 23, 2020
227
80
38
Seattle, Wa
Aug 24, 2023
#5
  • Aug 24, 2023
  • #5
Agreed with the wire connection issue, drove the car today and it had absolutely zero problems, no CEL either. I'll go over the harness.
 
You must log in or register to reply here.

Similar threads

C
Engine Idle cuts out
  • claypoolxx
  • Mar 7, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
25
Views
746
Fox 5.0 Mustang Tech Friday at 5:04 PM
alutwon
8
Engine Rough idle and aggressive sputtering when accelerating
  • 88vertible
  • Aug 13, 2025
  • Fox 5.0 Mustang Tech
Replies
4
Views
1K
Fox 5.0 Mustang Tech Dec 13, 2025
Jarhead67
J
S
Fuel ‘88 GT Runs Rich Cold — Fixes Itself When I Unplug Sensors (ECT, MAF, O2, etc.)
  • Sufarry
  • Nov 6, 2025
  • Fox 5.0 Mustang Tech
Replies
12
Views
844
Fox 5.0 Mustang Tech Nov 9, 2025
Mustang5L5
Engine Surging idle only on start up
  • keel
  • Jun 18, 2024
  • Fox 5.0 Mustang Tech
  • 2
Replies
33
Views
4K
Fox 5.0 Mustang Tech Sep 14, 2025
keel
M
Engine Unexplainable Exhaust Pop and Gurgle
  • Mrnissen122
  • Feb 14, 2026
  • Fox 5.0 Mustang Tech
Replies
12
Views
565
Fox 5.0 Mustang Tech Feb 18, 2026
Noobz347
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?